1. Field of the Invention
The present invention relates to a method for manufacturing a head chip which is mounted on an ink-jet type recording apparatus applicable to, for example, a printer and a facsimile.
2. Description of the Related Art
Conventionally, an ink-jet type recording apparatus is known in the technical field, in which a recording head for jetting ink droplets from a plurality of nozzles is employed to record characters and/or images on a recording medium. In such an ink-jet type recording apparatus, the recording head positioned opposite to the recording medium is provided on a head holder, and this head holder is mounted on a carriage so as to be scanned along a direction perpendicular to a transport direction of the recording medium.
In FIG. 12, there is shown an exploded/perspective view of one example of such a recording head. FIGS. 13A and 13B are sectional view of a major portion of this recording head. FIG. 13A is a sectional view of the recording head taken along the longitudinal direction of side walls. FIG. 13B is a sectional view of the recording head taken along the thickness direction of side walls. A plurality of grooves 102 are arranged in a piezoelectric ceramic plate 101 in a parallel manner. The respective grooves 102 are separated from each other by side walls 103. One edge portion of each of the grooves 102 in the longitudinal direction is elongated up to one edge surface of the piezoelectric ceramic plate 101, whereas the other edge portion is not elongated up to the other edge surface of this piezoelectric ceramic plate, and a depth thereof gradually becomes shallow. Also, an electrode 105 used to apply a driving electric field is formed on surfaces of both the side walls 103 on the opening side within each of the grooves 102 along the longitudinal direction.
A cover plate 107 is jointed via an adhesive agent 109 to the grooves 102 of the piezoelectric ceramic plate 101 on the opening side. This cover plate 107 has an ink chamber 111 that constitutes a concave portion which is communicated to the shallow other edge portion of each of the grooves 102 and an ink supply port 112 that is penetrated through a bottom portion of this ink chamber 111 along a direction opposite to the direction of the grooves 102.
A nozzle plate 115 is jointed on an edge surface of a joint member made by the piezoelectric ceramic plate 101 and the cover plate 107, at which the grooves 102 are opened. Nozzle openings 117 are formed in the nozzle plate 115 at such positions located opposite to the respective grooves 102.
It should be noted that a wiring board 120 is fixed on such a surface of the piezoelectric ceramic plate 101, which is located opposite to the nozzle plate 115 and also opposite to the cover plate 107. A wiring line 122 which is electrically connected to each of the electrodes 105 by employing a bonding wire 121 or the like is formed on the wiring board 120. A driver voltage may be applied via this wiring line 122 to the electrode 105.
In the recording head constituted in this manner, when ink is filled from the ink supply port 112 into the respective grooves 102 and a predetermined driving electric field is applied via the electrode 105 to the side walls 103 on both sides of a predetermined groove 102, the side walls 103 are deformed, so that a capacity formed within this predetermined groove 102 is change. As a result, the ink filled inside the grooves 102 may be jetted from the nozzle opening 117.
For example, as shown in FIG. 14, in the case where ink is jetted from a nozzle opening 117 corresponding to a groove 102a, a positive driving voltage is applied to both electrodes 105a and 105b provided in the groove 102a, and also electrodes 105c and 105d located opposite to these electrodes 105a and 105b are grounded. As a consequence, a driving electric field directed to the groove 102a is effected to the side walls 103a and 103b. When this driving electric field is positioned perpendicular to the polarization direction of the piezoelectric ceramic plate 101, both the side walls 103a and 103b are deformed along the direction of the groove 102a due to the piezoelectric thickness slip effect, so that the capacity defined inside the groove 102a is reduced to there by increase pressure. Thus, the ink may be jetted from the nozzle opening 117.
However, since such a head chip employs a large amount of high-cost ceramic, there is a problem in that the manufacturing cost of the head chip is high.
To solve such a problem, Japanese Patent Examined Publication No. Hei 6-6375 has proposed such a head chip which is manufactured by the plate-shaped board made of glass, piezoelectric ceramic plate made by arranging the pressure chambers in the array form on this plate-shaped board, and ink chamber plate made of glass.
In accordance with this head chip, since both the plate-shaped board and the ink chamber plate are made of low-cost glass materials, the head chip can be manufactured economically and the manufacturing time can be shortened.
However, in the foregoing head chip having the glass board, since the electrode for applying the voltage to the piezoelectric ceramic plate has to formed by oblique vapor deposition, the manufacturing cost is increased.
Furthermore, when the wiring lines electrically conducted to this electrode are extracted, these wiring lines are processed by metal plating such as nickel plating or gold plating, and thereafter the metal plated-wiring lines has to be cut one by one by using a laser. Thus, there is another problem in that the process step becomes cumbersome, and the manufacturing cost is increased.
Furthermore, even when the wiring lines are directly formed on the glass board by way of the metal plating, there is another problem in that the fitting characteristic is deteriorated, and thus, the formed wiring lines may readily peel off from the glass board.
The present invention has been made to solve the foregoing problems in the conventional art, and it is an object of the present invention to provide a method of manufacturing a head chip economically and in a simplified manner.
In order to solve the above problems, according to a first aspect of the present invention, there is provided a method of manufacturing a head chip, in which partition walls made of piezoelectric ceramic are arranged in a predetermined interval between a first upper board and a second lower board, which are made of a dielectric material; chambers are defined among the respective partition walls; and a wiring line is provided on a surface of any one of the first board and the second board, and is electrically conducted to an electrode formed on a side surface of the partition wall, and also is elongated up to an outer side of an edge portion of the partition wall along a longitudinal direction; the manufacturing method characterized by comprising:
a step in which the electrode and a metal film which constitutes a portion of the wiring line are formed by way of selective electroless plating, and these electrode and wiring line are electrically conducted to each other.
According to a second aspect of the present invention, in the first aspect of the present invention, there is provided a manufacturing method of a head chip characterized in that:
at least in a region corresponding to the chamber, the inorganic conductive film is formed on a portion located opposite to both edge portions of the partition wall in a width direction such that one side surface of the inorganic conductive film is exposed a long a longitudinal direction of the partition wall; and
the electrode is electrically conducted to at least the one side surface of the inorganic conductive film, which is exposed.
According to a third aspect of the present invention, in the second aspect of the present invention, there is provided a manufacturing method of a head chip characterized in that:
the electrode is formed byway of selective electroless plating such that the electrode is made in contact with the exposed one side surface of the inorganic conductive film to thereby be electrically conducted to the inorganic conductive film; and also the metal film is formed on the inorganic conductive film of the outer side of the partition wall along the longitudinal direction, whereby the electrode is electrically and mutually conducted via the inorganic conductive film to the metal film.
According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, there is provided a manufacturing method of a head chip, characterized by further comprising, prior to the step of forming the electrode and the metal film:
a step of forming an inorganic conductive film having a predetermined shape, which constitutes a portion of the wiring line, on any one of the first board and the second board; and
a step of providing the partition wall on the one board where the inorganic conductive film is formed.
According to a fifth aspect of the present invention, in any one of the first to third aspects of the present invention, there is provided a manufacturing method of a head chip characterized in that:
the step for forming the partition wall includes:
a step of joining a piezoelectric ceramic plate corresponding to a block which constitutes a plurality of partition walls on any one of the first board and the second board; and
a step of cutting the piezoelectric ceramic plate to form a plurality of partition walls.
According to a sixth aspect of the present invention, in the fifth aspect of the present invention, there is provided a manufacturing method of a head chip characterized in that:
the piezoelectric ceramic plate is jointed on the one board where the inorganic conductive film is formed, and both the piezoelectric ceramic plate and the one board located up to a portion of the one board in the thickness direction are removed, whereby the plurality of portion walls are formed.
According to a seventh aspect of the present invention, in any one of the first to third aspects of the present invention, there is provided a manufacturing method of a head chip characterized in that:
the dielectric material is glass.
According to a eighth aspect of the present invention, in any one of the first to third aspects of the present invention, there is provided a manufacturing method of a head chip characterized in that:
the inorganic conductive film is made of at least one sort of material selected from the group consisting of ITO, Sn, O2, ZnO, and ATO.
According to a ninth aspect of the present invention, in any one of the first to third aspects of the present invention, there is provided a manufacturing method of a head chip characterized in that:
a thickness of the inorganic conductive film is set to be equal to or thinner than 3 xcexcm.
According to a tenth aspect of the present invention, in any one of the first to third aspects of the present invention, there is provided a manufacturing method of a head chip characterized in that:
the partition wall is formed by adhering two members, which have different polarization, to each other.
According to a eleventh aspect of the present invention, in any one of the first to third aspects of the present invention, there is provided a manufacturing method of a head chip characterized in that:
both the electrode and the metal film are made of at least one material selected from nickel and gold.
According to a twelfth aspect of the present invention, in any one of the first to third aspects of the present invention, there is provided a manufacturing method of ahead chip, characterized by further comprising a step of providing a nozzle plate on one opening end of the chamber along a longitudinal direction of the partition wall, the nozzle plate having nozzle openings which are communicated to the respective chambers.
According to a thirteenth aspect of the present invention, in the twelfth aspect of the present invention, there is provided a manufacturing method of a head chip characterized in that:
the nozzle plate is made of a dielectric material.
In accordance with the manufacturing method of the present invention, while the board made of the dielectric material is employed, the inorganic conductive film, that has the better fitting characteristic with the dielectric material, is provided at the lowermost layer of the wiring line. As a consequence, the manufacturing step can be made simple, and also the manufacturing cost can be reduced. Moreover, the wiring lines can be easily and firmly conducted to the electrodes.